I just bought a 2003 BMW 525i. It did not have navigation.

Is it possible to add factory navigation.

How hard is it?
I see people sell factory navigation on ebay.

Any thoughts?

When I enquired about this on Ebay the bloke selling the factory equipment was an ex-BMW technician and provided a fitting service......I gave up on the idea because of the cost........

It can be done and i am sure your dealer will do it for you ( for an arm and both legs!)

Jim